Abstract: The invention provides a method of frying food by immersing it in a bath of boiling oil, wherein at the same time as cold food is introduced into the bath, oil which has cooled in contact with the food is withdrawn from the bath and separately reheated before being reintroduced into the bath.The invention also provides a deep-fryer for carrying out the method, the deep-fryer having a looped circulation duct which receives oil from part of a bottom portion of the oil bath and delivers the oil to another part of the bath, and means for heating oil passing through part of the circulation duct so that the oil flows in the duct due to a thermosiphon effect.